ppmtosixel(1) ppmtosixel(1)
NAME
ppmtosixel - convert a portable pixmap into DEC sixel for-
mat
SYNOPSISppmtosixel [-raw] [-margin] [ppmfile]
DESCRIPTION
Reads a portable pixmap as input. Produces sixel commands
(SIX) as output. The output is formatted for color print-
ing, e.g. for a DEC LJ250 color inkjet printer.
If RGB values from the PPM file do not have maxval=100,
the RGB values are rescaled. A printer control header and
a color assignment table begin the SIX file. Image data
is written in a compressed format by default. A printer
control footer ends the image file.
OPTIONS-raw If specified, each pixel will be explicitly
described in the image file. If -raw is not speci-
fied, output will default to compressed format in
which identical adjacent pixels are replaced by
"repeat pixel" commands. A raw file is often an
order of magnitude larger than a compressed file
and prints much slower.
-margin
If -margin is not specified, the image will be
start at the left margin (of the window, paper, or
whatever). If -margin is specified, a 1.5 inch
left margin will offset the image.
PRINTING
Generally, sixel files must reach the printer unfiltered.
Use the lpr -x option or cat filename > /dev/tty0?.
BUGS
Upon rescaling, truncation of the least significant bits
of RGB values may result in poor color conversion. If the
original PPM maxval was greater than 100, rescaling also
reduces the image depth. While the actual RGB values from
the ppm file are more or less retained, the color palette
of the LJ250 may not match the colors on your screen.
This seems to be a printer limitation.
SEEALSO
ppm(5)
AUTHOR
Copyright (C) 1991 by Rick Vinci.
26 April 1991 1